International patents relating to systems for explosive compositions are known in the prior art. This is the case for U.S. Pat. No. 5,500,062 made for an explosive emulsion. Such invention relates a mixed surfactant system for use in explosives in emulsion which provides stability for the emulsion as it is a surfactant and a co-surfactant, wherein each of them contains hydrocarbon chain groups. The first surfactant has groups with tail chains significantly longer than the co-surfactant and wherein the surfactants are based on an alkenyl succinic anhydride with a beta interaction parameter less than zero.
Moreover, U.S. Pat. No. 4,456,492 discloses a molten state explosive composition that includes, as its first component, a molten mass which can be poured, pumped or flowed at a temperature in a ratio from −10° C. to +90° C. and comprising at least one oxygen-releasing salt, for example, ammonium nitrate, and at least one mass-soluble combustible material, e.g. urea, and an ammonium nitrate-accepted granules as its second component. The explosive composition offers the advantage of using relatively inexpensive fuel as secondary fuel in an explosive composition, which is in molten state without loss of sensitivity to the detonation of the composition during storage. The explosive compositions also show appropriate sensitivity retention to detonation under conditions of static pressure applied in deep explosive wells.
Likewise, U.S. Pat. No. 4,401,490 refers to a molten explosive composition, i.e., the composition is in fluid state and comprises at least one oxygen-releasing salt, like the ammonium nitrate; at least one combustible material soluble in melting, such as, for example, urea; and at least one naphthalenesulfonate derivative selected from formaldehyde condensates and naphthalenesulfonic acids and their alkaline and alkaline earth metal salts, e.g. disodium methylene-bis (naphthalene-beta-sulphonic) and wherein the explosive compositions show a better sensitivity to detonation in small diameter explosive wells.
In addition, U.S. Pat. No. 4,434,017 relates an explosive composition and its preparation, wherein the explosive compositions do not contain water and comprise an oxidizing salt, a combustible material miscible with the salt in the liquid state and further contains gaseous bubbles.
Furthermore, U.S. Pat. No. 4,822,433 describes an explosive composition in emulsion stage, wherein it contains an oxygen supplying component in the discontinuous phase and, in the continuous phase, it is constituted by an organic medium, wherein the oxygen supplying component and the organic medium are capable of forming an emulsion which in the absence of a supplementary adjuvant shows an average conductivity at 60° C. which is not greater than 60,000 picomhos/meter due to the presence of a modifier.
In addition, granulated explosive mixtures with anfo grade ammonium nitrate with a density ranging from 0.65 g/cm3 to 0.80 g/cm3 are known and packed in plastic sleeves or in bags of diameters greater than 2½ inches (65 mm) and pumpable for diameters greater than 3″ (75 mm). However, these mixtures present the technical problem of not being sensitive to a 1″×8″ (25.4 mm×203.2 mm) Emulsion or Dynamite cartridge but to a ⅓ pound (0.15 kg) booster for its initiation as column load.
Given all that, it is evident that the unmet need for explosive compositions susceptible of being pumped through pumping equipment for underground mining still exists in the state of the art, wherein the composition presents an improved stability in its handling time, as well as the need for compositions with improved explosion energy and increased gas volumes allowing improved fragmentation of the rock material.